Transformer fuse mounting



,J. L. PAULUS TRANSFORMER 'FUSE MOUNTING March 25, 1969 Filed July 28. 1966 INVENTOR, drzjr-ee P205445 :xfitzoraa. a.

United States Patent 3,435,291 TRANSFORMER FUSE MOUNTING Jerry Lee Paulus, Zanesville, Ohio, assignor to McGraw- Edison Company, Milwaukee, Wis., a corporation of Delaware Filed July 28, 1966, Ser. No. 568,660 Int. Cl. H02h 7/04 US. Cl. 317- 8 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a fuse mounting for distribution transformers. An insulating mounting board is secured within the transformer and a tubular fuse is mounted to the board at the lower end by a suitable releasable clip such as a U-shaped clip. A quick disconnect slip connector is secured to the lower end of the fuse. A fuse mounting pin is secured to the top end of the mounting board and interconnected to and within a downwardly opening U-shaped spring. The fuse link includes an apertured tab to mate with the pin with the lower end of the fuse 'held within the U-shaped spring. The upper spring overlies the outer face of the pin and resiliently holds the fuse tab in electrical and physical support to the fuse pin.

This invention relates to a transformer fuse mounting and particularly to an improved mounting arrangement for supporting of a protective fuse within a high voltage transformer in a manner permitting ready, rapid and safe replacement of the fuse in the event of outage. I

Power distribution transformers and the like include transformer structures mounted within a suitable housing. A primary fuse link may be mounted within the transformer housing and interconnected to the high power primary line to provide protection of the transformer.

In known structures, the fuse unit is interconnected to a suitable mounting normally through a bolt type interconnection such that in order to remove the assembly the opposite ends of the terminal must be released from their connections, the connecting bolt and nut loosened or removed to release the fuse assembly. This was either done with the transformer cover removed or through a handhole cover in the tank. If care is not employed, the lineman might drop the attachment bolt and nut or the tool used to loosen the attachment means within the housing which of course must be found and removed before the system can be placed back in operation. Even if the attachment means or tool is not dropped, the several sequential operations are relatively time consuming and result in undesirable down time of the system.

The present invention is particularly directed to a primary fuse mounting for distribution transformers and the like which permit removal of the fuse without the necessity of any tools and in a very rapid and reliable manner.

Generally, in accordance with the present invention, the fuse is secured to an insulating mounting board which in turn is secured within the transformer unit. The fuse is mounted to the board at the lower end by a suitable releasable clip .such as a U-shaped clip adapted to resiliently grasp the opposite sides of the lower end of the fuse and support the lower end of the fuse. A quick disconnect connector is secured to the lower end of the fuse.

The lower end of the quick disconnect connector interconnection preferably includes a U-shaped tab member secured to the mounting board. A fuse pigtail is interconnected to the lower end of the fuse link and provided with a slip type connection for interconnection to the one side of the tab. A transformer coil lead is interconected to the opposite side of the tab. The fuse includes the usual fuse link and terminates at the top in a contact member connected to a combined support and terminal by slot and pin type interconnection. In a particularly satisfactory construction, a fuse mounting pin is secured to the top end of the mounting board and interconected to and within a downwardly opening U-shaped spring fuse holder and line terminal. The upper projection of the fuse link is provided with an opening adapted to mate with the pin 2 with the lower end of the fuse held within the U- shaped or the lower spring holder. The upper spring overlies the outer face of the pin and resiliently holds the fuse in electrical and physical support to the fuse mounting pin 2.

The upper end is thus physically supported and electrically connected to the line terminal for interconnection in the circuit.

In use, when it is desired to remove and replace the fuse, the operator removes a cover and then removes the one quick disconnect connector at the lower end of the fuse, grasps the fuse, pulls and twists to remove the fuse from the lower and the upper clip. This permits very rapid removal and replacement of the fuse, thereby reducing down time of the transformer, and also eliminates the danger of dropping of a part within the transformer.

The drawing furnished herewith, illustrates a preferred construction of the present invention in which the above advantages and features are clearly disclosed as well as others which will be clear from the following description.

In the drawing:

FIG. 1 is a side elevational diagrammatic view of a power distribution transformer with parts broken away to show an improved fuse mounting assembly constructed in accordance with the present invention;

FIG. 2 is an enlarged front elevational View of the fuse mounting assembly shown in FIG. 1;

FIG. 3 is a top view of FIG. 2; and

FIG. 4 is a side elevational view of FIG. 2.

Referring to the drawing and particularly to FIG. 1, a typical power distribution transformer unit is shown including an outer open top tank 1 within which a suitable transformer 2 is mounted in any suitable manner. In the illustrated embodiment of the invention, an upper clamping unit 3 is provided to rigidly support the upper end of the transformer 2 within the tank 1. The upper end of the tank 1 is closed by a cover 4 which is bolted or otherwise secured to the tank 1 and includes a releasably mounted handhole cover 5 permitting access to the interior of the tank without complete removal of the cover 4. A protective fuse assembly 6 is mounted to the support 3 within the tank 1 and located to permit ready access through the opening covered by the handhole cover 5. The protective fuse assembly '6 and its mounting particularly for-ms the subject matter of the present invention. As the transformer 2 and its mounting may be of any known or desired construction, no further detailed description of the unit is given herein.

The fuse assembly 6 is more fully shown in FIGS. 2-4.

Generally, the fuse assembly includes a mounting board 7 shown as a rectangular mounting board formed of a plastic or other suitable insulating material. An ls-shaped mounting bracket 8 includes a vertical arm secured along one edge of the mounting plate, as by self tapping screws 9. The secured arm of member 8 is disposed below the lower edge of board 7 and extends horizontally thereof. The second arm is secured to the core clamping unit 3 within the tank 1 as by suitable nut and bolt units 10 to mount the fuse assembly 6 within the tank 1 adjacent the handhole cover 5.

A protective fuse 11 is releasably secured along the opposite edge of the mounting board 7. The fuse 11 is a tubular fuse having the usual fusible link which extends through the fuse and terminates in a lower end terminal 12 and an upper end terminal 13. The terminals 12 and '13 are generally strip-like members which extend diametrically of the fuse 11.

In accordance with the illustrated embodiment of the invention, the lower end of the fuse 11 is supported by a generally U-shaped clip 14 and the upper end by a combined fuse holder and line terminal assembly 15 to electrically interconnect the terminal 13 to a power line 16 and to physically support the upper end of the fuse 11.

The assembly 15 includes a contact stake 17 extending through a suitable opening in the top edge portion of the mounting board 7 and includes a clamping head to the back side of the mounting board 7. A contact pin 18 is provided on the opposite side of the mounting board 7 and press fitted or otherwise secured to the stake 17 to rigidly mount the pin in place. The pin 18 includes a head abutting the mounting board 7 and an outer reduced portion of a length generally corresponding to the thickness of the upper end terminal 13-. An aperture 19 slightly larger than the diameter of the reduced portion of pin 18 is adapted to mate and mesh therewith as shown in the drawings.

An generally U -shaped clip 20 of a suitable spring metal overlies the upper edge of the mounting board 7. The one arm of the spring clip 20 lies adjacent the back side of mounting board 7 with stake 17 passing through to an opening to clamp the arm to the board 7. A washer 21 is disposed between the head of the stake 17 and the arm of the spring clip 20.

The back end of the side arm is bent outwardly to form a connection tap 22 to which the line 16 is connected in any suitable manner. The base of the clip 20 projects forwardly over the mounting board and the pin 18 to locate the outer or opposite arm 23 overlying the forward end of the pin 18 as most clearly shown in FIG. 4. The arm 23 is curved to pass the pin and defining a lower clamping surface normally stressed to lie beneath the reduced portion of pin 17, as shown in phantom in FIG. 4. The clip 20 thus engages the fuse terminal 13 immediately below the pin 17 and resiliently holds it in mating engagement with the contact pin 18, as shown in FIG. 4. This establishes a resilient pin and slot type support for the fuse 11 and also provides an electrical contact to the incoming power lea-d 16 through the pin 18 and spring clip 20 to the lead 16. The terminal 13 can be disengaged by merely moving the fuse 11 to disengage the pin 18 from the aperture 19 and pulling laterally or downwardly of clip 20. Conveniently, the fuse 11 can be twisted about the vertical axis and then pulled from between the pin 18 and clip 20.

The lower end of the fuse 11 is supported by the U- shaped clip 14 which has one arm secured to the mounting board 7 as by rivets 24. The clip 14 opens laterally of the upper clip 20 and permits lateral movement of the fuse 11 with respect to the upper pin mounting.

The lower end terminal 12 of the fuse 11 projects downwardly below the clip 14 and the lower edge of the board 7. A connecting pigtail 25 is soldered or otherwise attached to the terminal 12 as at 26 and is interconnected to a second power lead 27 through a quick disconnect U- shaped tab 28. The base of tab 28 is secured to the front of mounting board 7 adjacent the fuse clip 14 as by rivets 29. The side arms of the tab 28 project forwardly and constitute connecting arms. A bayonet quick disconnect terminal is clamped to the pigtail 25 and includes a conventional receptacle 30 formed with a base portion and generally J-shaped side edges for telescopic connection to the one arm of tab 28, as most clearly shown in FIGS. 2 and 3.

The power lead 27 is shown similarly connected to the opposite arm of the tab 28.

The mounting board 7 which is secured within the tank provides an insulated support for the fuse assembly 6. In use, the upper terminal assembly 15 supports the upper end of the fuse 11 and provides electrical connection to the lead 16. The lower end of the fuse 11 is secured within the U-shaped clip 14 and interconnected through the quick disconnect bayonet connection to the tab 28 for interconnection to the transformer coil lead 27. To replace the fuse 11, the lineman removes the handhole cover 5 to obtain access to the interior of the tank .1 and particularly the assembly 6. The disconnect bayonet receptacle is removed from the tab 28. The fuse is then grasped, between the clip 14 and assembly 15, the lower end pulled from the clip '14, the fuse 11 twisted to disengage the upper terminal 13 from the pin 18 and then pulled laterally or downwardly of the upper clip 20 to completely release the fuse 11. Similarly, to replace the fuse, the lineman merely inserts the upper end terminal 13 between the pin 18 and the upper clip arm 23, forces the arm 23 outwardly to permit insertion of the terminal 13 on the pin 18 and pivots the lower end of fuse11 into the clip 14. The quick disconnect receptacle is attached to the corresponding arm of the tab 28 to complete the replacement of the fuse.

The removal and insertion of the fuse 11 is thus done manually and without the necessity of any auxiliary equipment or tools and without the removal of any components other than the fuse proper. The fuse mounting unit of this invention provides a reliable mounting within a transformer for normal operation while permitting rapid removal of the unit with a minimum amount of time.

I claim:

1. In a fuse-protected transformer having a tank with an access opening, the improvement in a fuse assembly for securing an elongated fuse within the tank, said fuse having a terminal member, comprising a fixed supporting terminal means secured to the mounting means, a first spring means overlying the supporting terminal means and adapted to have said terminal member disposed between said terminal means and said spring to resiliently hold the fuse terminal member in abutting electrical and supporting engagement to the fixed supporting terminal means,

a second spring means secured to the mounting member to releasably and resiliently grasp the opposite end of the fuse and permit removal of the fuse therefrom without the use of a tool, and

said first and second spring means permitting manual removal of the fuse from the mounting member without the use of tools.

2. In the improvement in the fuse-protected transformer of claim 1, wherein the fuse includes a second terminal member and including,

a quick disconnect connector mounted adjacent the second spring means and having a slip-type resiliently mounted connecting element interconnected by a lead means to said second terminal member.

3. In the fuse-protected transformer of claim 1, wherein the first spring member is a generally U-shaped clip opening downwardly and overlying the supporting terminal means with one arm depending downwardly past the terminal means and with said terminal member disposed between the terminal means and the one arm of clip, and

the second spring member is a generally U-shaped clip opening laterally of the first spring member.

4. The fuse-protected transformer of claim 1, wherein the fuse terminal member is a plate-like member having a connecting opening,

said terminal means includes a pin adapted to mate with the opening, and

said first spring member is a flexible arm overlying the pin to hold the terminal member in the pin.

5. In the fuse-protected transformer of claim 4, wherein said pin is a stepped pin having a reduced outer portion of a diameter slightly less than the opening in the terminal plate and a length corresponding to the thickness of the terminal plate, and

said spring member is a U-shaped clip overlying the terminal pin.

6. The fuse-protected transformer of claim 1, wherein the fuse terminal member is a plate-like member having a connecting opening,

the supporting terminal means includes a stepped pin secured to the upper forward face of the mounting board by a stake projecting through an opening in the board, said first spring member overlies the upper edge of the board and the stepped pin with one arm said terminal means includes a pin adapted to mate 5 clamped between the stake and the back face of the with the opening, board and the other arm overlying and stressed tosaid first spring member is a flexible arm overlying ward the pin, said pin having an outermost reduced the pin to hold the terminal member in the pin, and diameter portion of a length corresponding to the said second spring means being a U-shaped clamping 10 thickness of the terminal member and a diameter means opening transversely of the pin to permit slightly less than the opening to receive said terminal pivoting of the use about said pin. member, said spring member resiliently clamping the 7. In the fuse-protected transformer of claim 1, wherein fuse terminal member in electrical and supporting the first-named fuse terminal member includes a plateengagement to the pin,

like terminal having a mounting opening and the said second spring member is a U-shaped clip having terminal means includes a pin secured to the mountone side arm secured to the mounting board and the ing means to mate with said opening with the outer opposite arm disposed outwardly to define an enend being coplanar with the outer face of the fuse trance opening along the edge of the board and to terminal, releasably and resiliently grasp the lower end of the said pin having a reduced outer portion of a diameter fuse and permit pivotal movement of the fuse about slightly less than the opening in the terminal plate the pin, and a length corresponding to the thickness of the v a pigtail secured to the second fuse terminal means, and terminal plate, and a bayonet connector including one member secured said first spring member is a U-shaped clip overlying to the outer end of the pigtail and a second member the terminal pin with the outer arm curved to insecured to the mounting board adjacent the second clude a portion aligned with and spaced outwardly spring member. of the pin and an outer end of the arm resiliently urged to a position between the fuse terminal end and f r n s C te 8 i ffi P t f h f d UNITED STATES PATENTS fom'ler of i g gffiigig t 6 use Pmtecte 2,984,723 5/1961 Jacobs 200-113 the first fuse terminal member projects from one end 32 8; et of the fuse as a plate like member having an open 3,292,048 12/1966 Swoish et a1 317 15 ing and a second fuse terminal means projects from the opposite end,

said mounting means including a generally rectangular board of material mounted in a generally vertical position by a mounting bracket secured to one edge, said fuse being mounted along the opposite edge,

35 JOHN F. COUCH, Primary Examiner.

I. D. TRAMMELL, Assistant Examiner.

Patent No. 3 ,435 ,291

March 25,

Jerry Lee Paulus hat error appears in the above identified It is certified 1:

t are hereby corrected as patent and that said Letters Paten shown below:

Column 5, line 12, "use" should read fuse Signed and sealed this 14th day of April 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER,

Edward M. Fletcher, 11'.

Commissioner of Pat Attesting Officer 

